block/blk-sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Functions related to sysfs handling
   4  */
   5 #include <linux/kernel.h>
   6 #include <linux/slab.h>
   7 #include <linux/module.h>
   8 #include <linux/bio.h>
   9 #include <linux/blkdev.h>
  10 #include <linux/backing-dev.h>
  11 #include <linux/blktrace_api.h>
  12 #include <linux/blk-mq.h>
  13 #include <linux/blk-cgroup.h>
  14 #include <linux/debugfs.h>
  15
  16 #include "blk.h"
  17 #include "blk-mq.h"
  18 #include "blk-mq-debugfs.h"
  19 #include "blk-wbt.h"
  20
  21 struct queue_sysfs_entry {
  22         struct attribute attr;
  23         ssize_t (*show)(struct request_queue *, char *);
  24         ssize_t (*store)(struct request_queue *, const char *, size_t);
  25 };
  26
  27 static ssize_t
  28 queue_var_show(unsigned long var, char *page)
  29 {
  30         return sprintf(page, "%lu\n", var);
  31 }
  32
  33 static ssize_t
  34 queue_var_store(unsigned long *var, const char *page, size_t count)
  35 {
  36         int err;
  37         unsigned long v;
  38
  39         err = kstrtoul(page, 10, &v);
  40         if (err || v > UINT_MAX)
  41                 return -EINVAL;
  42
  43         *var = v;
  44
  45         return count;
  46 }
  47
  48 static ssize_t queue_var_store64(s64 *var, const char *page)
  49 {
  50         int err;
  51         s64 v;
  52
  53         err = kstrtos64(page, 10, &v);
  54         if (err < 0)
  55                 return err;
  56
  57         *var = v;
  58         return 0;
  59 }
  60
  61 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  62 {
  63         return queue_var_show(q->nr_requests, (page));
  64 }
  65
  66 static ssize_t
  67 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  68 {
  69         unsigned long nr;
  70         int ret, err;
  71
  72         if (!queue_is_mq(q))
  73                 return -EINVAL;
  74
  75         ret = queue_var_store(&nr, page, count);
  76         if (ret < 0)
  77                 return ret;
  78
  79         if (nr < BLKDEV_MIN_RQ)
  80                 nr = BLKDEV_MIN_RQ;
  81
  82         err = blk_mq_update_nr_requests(q, nr);
  83         if (err)
  84                 return err;
  85
  86         return ret;
  87 }
  88
  89 static ssize_t queue_ra_show(struct request_queue *q, char *page)
  90 {
  91         unsigned long ra_kb = q->backing_dev_info->ra_pages <<
  92                                         (PAGE_SHIFT - 10);
  93
  94         return queue_var_show(ra_kb, (page));
  95 }
  96
  97 static ssize_t
  98 queue_ra_store(struct request_queue *q, const char *page, size_t count)
  99 {
 100         unsigned long ra_kb;
 101         ssize_t ret = queue_var_store(&ra_kb, page, count);
 102
 103         if (ret < 0)
 104                 return ret;
 105
 106         q->backing_dev_info->ra_pages = ra_kb >> (PAGE_SHIFT - 10);
 107
 108         return ret;
 109 }
 110
 111 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
 112 {
 113         int max_sectors_kb = queue_max_sectors(q) >> 1;
 114
 115         return queue_var_show(max_sectors_kb, (page));
 116 }
 117
 118 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 119 {
 120         return queue_var_show(queue_max_segments(q), (page));
 121 }
 122
 123 static ssize_t queue_max_discard_segments_show(struct request_queue *q,
 124                 char *page)
 125 {
 126         return queue_var_show(queue_max_discard_segments(q), (page));
 127 }
 128
 129 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 130 {
 131         return queue_var_show(q->limits.max_integrity_segments, (page));
 132 }
 133
 134 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 135 {
 136         return queue_var_show(queue_max_segment_size(q), (page));
 137 }
 138
 139 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 140 {
 141         return queue_var_show(queue_logical_block_size(q), page);
 142 }
 143
 144 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 145 {
 146         return queue_var_show(queue_physical_block_size(q), page);
 147 }
 148
 149 static ssize_t queue_chunk_sectors_show(struct request_queue *q, char *page)
 150 {
 151         return queue_var_show(q->limits.chunk_sectors, page);
 152 }
 153
 154 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 155 {
 156         return queue_var_show(queue_io_min(q), page);
 157 }
 158
 159 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 160 {
 161         return queue_var_show(queue_io_opt(q), page);
 162 }
 163
 164 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 165 {
 166         return queue_var_show(q->limits.discard_granularity, page);
 167 }
 168
 169 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
 170 {
 171
 172         return sprintf(page, "%llu\n",
 173                 (unsigned long long)q->limits.max_hw_discard_sectors << 9);
 174 }
 175
 176 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 177 {
 178         return sprintf(page, "%llu\n",
 179                        (unsigned long long)q->limits.max_discard_sectors << 9);
 180 }
 181
 182 static ssize_t queue_discard_max_store(struct request_queue *q,
 183                                        const char *page, size_t count)
 184 {
 185         unsigned long max_discard;
 186         ssize_t ret = queue_var_store(&max_discard, page, count);
 187
 188         if (ret < 0)
 189                 return ret;
 190
 191         if (max_discard & (q->limits.discard_granularity - 1))
 192                 return -EINVAL;
 193
 194         max_discard >>= 9;
 195         if (max_discard > UINT_MAX)
 196                 return -EINVAL;
 197
 198         if (max_discard > q->limits.max_hw_discard_sectors)
 199                 max_discard = q->limits.max_hw_discard_sectors;
 200
 201         q->limits.max_discard_sectors = max_discard;
 202         return ret;
 203 }
 204
 205 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 206 {
 207         return queue_var_show(0, page);
 208 }
 209
 210 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 211 {
 212         return sprintf(page, "%llu\n",
 213                 (unsigned long long)q->limits.max_write_same_sectors << 9);
 214 }
 215
 216 static ssize_t queue_write_zeroes_max_show(struct request_queue *q, char *page)
 217 {
 218         return sprintf(page, "%llu\n",
 219                 (unsigned long long)q->limits.max_write_zeroes_sectors << 9);
 220 }
 221
 222 static ssize_t queue_zone_write_granularity_show(struct request_queue *q,
 223                                                  char *page)
 224 {
 225         return queue_var_show(queue_zone_write_granularity(q), page);
 226 }
 227
 228 static ssize_t queue_zone_append_max_show(struct request_queue *q, char *page)
 229 {
 230         unsigned long long max_sectors = q->limits.max_zone_append_sectors;
 231
 232         return sprintf(page, "%llu\n", max_sectors << SECTOR_SHIFT);
 233 }
 234
 235 static ssize_t
 236 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 237 {
 238         unsigned long max_sectors_kb,
 239                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 240                         page_kb = 1 << (PAGE_SHIFT - 10);
 241         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 242
 243         if (ret < 0)
 244                 return ret;
 245
 246         max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long)
 247                                          q->limits.max_dev_sectors >> 1);
 248
 249         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 250                 return -EINVAL;
 251
 252         spin_lock_irq(&q->queue_lock);
 253         q->limits.max_sectors = max_sectors_kb << 1;
 254         q->backing_dev_info->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
 255         spin_unlock_irq(&q->queue_lock);
 256
 257         return ret;
 258 }
 259
 260 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 261 {
 262         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 263
 264         return queue_var_show(max_hw_sectors_kb, (page));
 265 }
 266
 267 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 268 static ssize_t                                                          \
 269 queue_##name##_show(struct request_queue *q, char *page)                \
 270 {                                                                       \
 271         int bit;                                                        \
 272         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 273         return queue_var_show(neg ? !bit : bit, page);                  \
 274 }                                                                       \
 275 static ssize_t                                                          \
 276 queue_##name##_store(struct request_queue *q, const char *page, size_t count) \
 277 {                                                                       \
 278         unsigned long val;                                              \
 279         ssize_t ret;                                                    \
 280         ret = queue_var_store(&val, page, count);                       \
 281         if (ret < 0)                                                    \
 282                  return ret;                                            \
 283         if (neg)                                                        \
 284                 val = !val;                                             \
 285                                                                         \
 286         if (val)                                                        \
 287                 blk_queue_flag_set(QUEUE_FLAG_##flag, q);               \
 288         else                                                            \
 289                 blk_queue_flag_clear(QUEUE_FLAG_##flag, q);             \
 290         return ret;                                                     \
 291 }
 292
 293 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 294 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 295 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 296 QUEUE_SYSFS_BIT_FNS(stable_writes, STABLE_WRITES, 0);
 297 #undef QUEUE_SYSFS_BIT_FNS
 298
 299 static ssize_t queue_zoned_show(struct request_queue *q, char *page)
 300 {
 301         switch (blk_queue_zoned_model(q)) {
 302         case BLK_ZONED_HA:
 303                 return sprintf(page, "host-aware\n");
 304         case BLK_ZONED_HM:
 305                 return sprintf(page, "host-managed\n");
 306         default:
 307                 return sprintf(page, "none\n");
 308         }
 309 }
 310
 311 static ssize_t queue_nr_zones_show(struct request_queue *q, char *page)
 312 {
 313         return queue_var_show(blk_queue_nr_zones(q), page);
 314 }
 315
 316 static ssize_t queue_max_open_zones_show(struct request_queue *q, char *page)
 317 {
 318         return queue_var_show(queue_max_open_zones(q), page);
 319 }
 320
 321 static ssize_t queue_max_active_zones_show(struct request_queue *q, char *page)
 322 {
 323         return queue_var_show(queue_max_active_zones(q), page);
 324 }
 325
 326 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 327 {
 328         return queue_var_show((blk_queue_nomerges(q) << 1) |
 329                                blk_queue_noxmerges(q), page);
 330 }
 331
 332 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 333                                     size_t count)
 334 {
 335         unsigned long nm;
 336         ssize_t ret = queue_var_store(&nm, page, count);
 337
 338         if (ret < 0)
 339                 return ret;
 340
 341         blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 342         blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 343         if (nm == 2)
 344                 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 345         else if (nm)
 346                 blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 347
 348         return ret;
 349 }
 350
 351 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 352 {
 353         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 354         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 355
 356         return queue_var_show(set << force, page);
 357 }
 358
 359 static ssize_t
 360 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 361 {
 362         ssize_t ret = -EINVAL;
 363 #ifdef CONFIG_SMP
 364         unsigned long val;
 365
 366         ret = queue_var_store(&val, page, count);
 367         if (ret < 0)
 368                 return ret;
 369
 370         if (val == 2) {
 371                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 372                 blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 373         } else if (val == 1) {
 374                 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 375                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 376         } else if (val == 0) {
 377                 blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 378                 blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 379         }
 380 #endif
 381         return ret;
 382 }
 383
 384 static ssize_t queue_poll_delay_show(struct request_queue *q, char *page)
 385 {
 386         int val;
 387
 388         if (q->poll_nsec == BLK_MQ_POLL_CLASSIC)
 389                 val = BLK_MQ_POLL_CLASSIC;
 390         else
 391                 val = q->poll_nsec / 1000;
 392
 393         return sprintf(page, "%d\n", val);
 394 }
 395
 396 static ssize_t queue_poll_delay_store(struct request_queue *q, const char *page,
 397                                 size_t count)
 398 {
 399         int err, val;
 400
 401         if (!q->mq_ops || !q->mq_ops->poll)
 402                 return -EINVAL;
 403
 404         err = kstrtoint(page, 10, &val);
 405         if (err < 0)
 406                 return err;
 407
 408         if (val == BLK_MQ_POLL_CLASSIC)
 409                 q->poll_nsec = BLK_MQ_POLL_CLASSIC;
 410         else if (val >= 0)
 411                 q->poll_nsec = val * 1000;
 412         else
 413                 return -EINVAL;
 414
 415         return count;
 416 }
 417
 418 static ssize_t queue_poll_show(struct request_queue *q, char *page)
 419 {
 420         return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
 421 }
 422
 423 static ssize_t queue_poll_store(struct request_queue *q, const char *page,
 424                                 size_t count)
 425 {
 426         unsigned long poll_on;
 427         ssize_t ret;
 428
 429         if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL ||
 430             !q->tag_set->map[HCTX_TYPE_POLL].nr_queues)
 431                 return -EINVAL;
 432
 433         ret = queue_var_store(&poll_on, page, count);
 434         if (ret < 0)
 435                 return ret;
 436
 437         if (poll_on) {
 438                 blk_queue_flag_set(QUEUE_FLAG_POLL, q);
 439         } else {
 440                 blk_mq_freeze_queue(q);
 441                 blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
 442                 blk_mq_unfreeze_queue(q);
 443         }
 444
 445         return ret;
 446 }
 447
 448 static ssize_t queue_io_timeout_show(struct request_queue *q, char *page)
 449 {
 450         return sprintf(page, "%u\n", jiffies_to_msecs(q->rq_timeout));
 451 }
 452
 453 static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page,
 454                                   size_t count)
 455 {
 456         unsigned int val;
 457         int err;
 458
 459         err = kstrtou32(page, 10, &val);
 460         if (err || val == 0)
 461                 return -EINVAL;
 462
 463         blk_queue_rq_timeout(q, msecs_to_jiffies(val));
 464
 465         return count;
 466 }
 467
 468 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
 469 {
 470         if (!wbt_rq_qos(q))
 471                 return -EINVAL;
 472
 473         return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
 474 }
 475
 476 static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
 477                                   size_t count)
 478 {
 479         struct rq_qos *rqos;
 480         ssize_t ret;
 481         s64 val;
 482
 483         ret = queue_var_store64(&val, page);
 484         if (ret < 0)
 485                 return ret;
 486         if (val < -1)
 487                 return -EINVAL;
 488
 489         rqos = wbt_rq_qos(q);
 490         if (!rqos) {
 491                 ret = wbt_init(q);
 492                 if (ret)
 493                         return ret;
 494         }
 495
 496         if (val == -1)
 497                 val = wbt_default_latency_nsec(q);
 498         else if (val >= 0)
 499                 val *= 1000ULL;
 500
 501         if (wbt_get_min_lat(q) == val)
 502                 return count;
 503
 504         /*
 505          * Ensure that the queue is idled, in case the latency update
 506          * ends up either enabling or disabling wbt completely. We can't
 507          * have IO inflight if that happens.
 508          */
 509         blk_mq_freeze_queue(q);
 510         blk_mq_quiesce_queue(q);
 511
 512         wbt_set_min_lat(q, val);
 513
 514         blk_mq_unquiesce_queue(q);
 515         blk_mq_unfreeze_queue(q);
 516
 517         return count;
 518 }
 519
 520 static ssize_t queue_wc_show(struct request_queue *q, char *page)
 521 {
 522         if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
 523                 return sprintf(page, "write back\n");
 524
 525         return sprintf(page, "write through\n");
 526 }
 527
 528 static ssize_t queue_wc_store(struct request_queue *q, const char *page,
 529                               size_t count)
 530 {
 531         int set = -1;
 532
 533         if (!strncmp(page, "write back", 10))
 534                 set = 1;
 535         else if (!strncmp(page, "write through", 13) ||
 536                  !strncmp(page, "none", 4))
 537                 set = 0;
 538
 539         if (set == -1)
 540                 return -EINVAL;
 541
 542         if (set)
 543                 blk_queue_flag_set(QUEUE_FLAG_WC, q);
 544         else
 545                 blk_queue_flag_clear(QUEUE_FLAG_WC, q);
 546
 547         return count;
 548 }
 549
 550 static ssize_t queue_fua_show(struct request_queue *q, char *page)
 551 {
 552         return sprintf(page, "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags));
 553 }
 554
 555 static ssize_t queue_dax_show(struct request_queue *q, char *page)
 556 {
 557         return queue_var_show(blk_queue_dax(q), page);
 558 }
 559
 560 #define QUEUE_RO_ENTRY(_prefix, _name)                  \
 561 static struct queue_sysfs_entry _prefix##_entry = {     \
 562         .attr   = { .name = _name, .mode = 0444 },      \
 563         .show   = _prefix##_show,                       \
 564 };
 565
 566 #define QUEUE_RW_ENTRY(_prefix, _name)                  \
 567 static struct queue_sysfs_entry _prefix##_entry = {     \
 568         .attr   = { .name = _name, .mode = 0644 },      \
 569         .show   = _prefix##_show,                       \
 570         .store  = _prefix##_store,                      \
 571 };
 572
 573 QUEUE_RW_ENTRY(queue_requests, "nr_requests");
 574 QUEUE_RW_ENTRY(queue_ra, "read_ahead_kb");
 575 QUEUE_RW_ENTRY(queue_max_sectors, "max_sectors_kb");
 576 QUEUE_RO_ENTRY(queue_max_hw_sectors, "max_hw_sectors_kb");
 577 QUEUE_RO_ENTRY(queue_max_segments, "max_segments");
 578 QUEUE_RO_ENTRY(queue_max_integrity_segments, "max_integrity_segments");
 579 QUEUE_RO_ENTRY(queue_max_segment_size, "max_segment_size");
 580 QUEUE_RW_ENTRY(elv_iosched, "scheduler");
 581
 582 QUEUE_RO_ENTRY(queue_logical_block_size, "logical_block_size");
 583 QUEUE_RO_ENTRY(queue_physical_block_size, "physical_block_size");
 584 QUEUE_RO_ENTRY(queue_chunk_sectors, "chunk_sectors");
 585 QUEUE_RO_ENTRY(queue_io_min, "minimum_io_size");
 586 QUEUE_RO_ENTRY(queue_io_opt, "optimal_io_size");
 587
 588 QUEUE_RO_ENTRY(queue_max_discard_segments, "max_discard_segments");
 589 QUEUE_RO_ENTRY(queue_discard_granularity, "discard_granularity");
 590 QUEUE_RO_ENTRY(queue_discard_max_hw, "discard_max_hw_bytes");
 591 QUEUE_RW_ENTRY(queue_discard_max, "discard_max_bytes");
 592 QUEUE_RO_ENTRY(queue_discard_zeroes_data, "discard_zeroes_data");
 593
 594 QUEUE_RO_ENTRY(queue_write_same_max, "write_same_max_bytes");
 595 QUEUE_RO_ENTRY(queue_write_zeroes_max, "write_zeroes_max_bytes");
 596 QUEUE_RO_ENTRY(queue_zone_append_max, "zone_append_max_bytes");
 597 QUEUE_RO_ENTRY(queue_zone_write_granularity, "zone_write_granularity");
 598
 599 QUEUE_RO_ENTRY(queue_zoned, "zoned");
 600 QUEUE_RO_ENTRY(queue_nr_zones, "nr_zones");
 601 QUEUE_RO_ENTRY(queue_max_open_zones, "max_open_zones");
 602 QUEUE_RO_ENTRY(queue_max_active_zones, "max_active_zones");
 603
 604 QUEUE_RW_ENTRY(queue_nomerges, "nomerges");
 605 QUEUE_RW_ENTRY(queue_rq_affinity, "rq_affinity");
 606 QUEUE_RW_ENTRY(queue_poll, "io_poll");
 607 QUEUE_RW_ENTRY(queue_poll_delay, "io_poll_delay");
 608 QUEUE_RW_ENTRY(queue_wc, "write_cache");
 609 QUEUE_RO_ENTRY(queue_fua, "fua");
 610 QUEUE_RO_ENTRY(queue_dax, "dax");
 611 QUEUE_RW_ENTRY(queue_io_timeout, "io_timeout");
 612 QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec");
 613
 614 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 615 QUEUE_RW_ENTRY(blk_throtl_sample_time, "throttle_sample_time");
 616 #endif
 617
 618 /* legacy alias for logical_block_size: */
 619 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 620         .attr = {.name = "hw_sector_size", .mode = 0444 },
 621         .show = queue_logical_block_size_show,
 622 };
 623
 624 QUEUE_RW_ENTRY(queue_nonrot, "rotational");
 625 QUEUE_RW_ENTRY(queue_iostats, "iostats");
 626 QUEUE_RW_ENTRY(queue_random, "add_random");
 627 QUEUE_RW_ENTRY(queue_stable_writes, "stable_writes");
 628
 629 static struct attribute *queue_attrs[] = {
 630         &queue_requests_entry.attr,
 631         &queue_ra_entry.attr,
 632         &queue_max_hw_sectors_entry.attr,
 633         &queue_max_sectors_entry.attr,
 634         &queue_max_segments_entry.attr,
 635         &queue_max_discard_segments_entry.attr,
 636         &queue_max_integrity_segments_entry.attr,
 637         &queue_max_segment_size_entry.attr,
 638         &elv_iosched_entry.attr,
 639         &queue_hw_sector_size_entry.attr,
 640         &queue_logical_block_size_entry.attr,
 641         &queue_physical_block_size_entry.attr,
 642         &queue_chunk_sectors_entry.attr,
 643         &queue_io_min_entry.attr,
 644         &queue_io_opt_entry.attr,
 645         &queue_discard_granularity_entry.attr,
 646         &queue_discard_max_entry.attr,
 647         &queue_discard_max_hw_entry.attr,
 648         &queue_discard_zeroes_data_entry.attr,
 649         &queue_write_same_max_entry.attr,
 650         &queue_write_zeroes_max_entry.attr,
 651         &queue_zone_append_max_entry.attr,
 652         &queue_zone_write_granularity_entry.attr,
 653         &queue_nonrot_entry.attr,
 654         &queue_zoned_entry.attr,
 655         &queue_nr_zones_entry.attr,
 656         &queue_max_open_zones_entry.attr,
 657         &queue_max_active_zones_entry.attr,
 658         &queue_nomerges_entry.attr,
 659         &queue_rq_affinity_entry.attr,
 660         &queue_iostats_entry.attr,
 661         &queue_stable_writes_entry.attr,
 662         &queue_random_entry.attr,
 663         &queue_poll_entry.attr,
 664         &queue_wc_entry.attr,
 665         &queue_fua_entry.attr,
 666         &queue_dax_entry.attr,
 667         &queue_wb_lat_entry.attr,
 668         &queue_poll_delay_entry.attr,
 669         &queue_io_timeout_entry.attr,
 670 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
 671         &blk_throtl_sample_time_entry.attr,
 672 #endif
 673         NULL,
 674 };
 675
 676 static umode_t queue_attr_visible(struct kobject *kobj, struct attribute *attr,
 677                                 int n)
 678 {
 679         struct request_queue *q =
 680                 container_of(kobj, struct request_queue, kobj);
 681
 682         if (attr == &queue_io_timeout_entry.attr &&
 683                 (!q->mq_ops || !q->mq_ops->timeout))
 684                         return 0;
 685
 686         if ((attr == &queue_max_open_zones_entry.attr ||
 687              attr == &queue_max_active_zones_entry.attr) &&
 688             !blk_queue_is_zoned(q))
 689                 return 0;
 690
 691         return attr->mode;
 692 }
 693
 694 static struct attribute_group queue_attr_group = {
 695         .attrs = queue_attrs,
 696         .is_visible = queue_attr_visible,
 697 };
 698
 699
 700 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 701
 702 static ssize_t
 703 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 704 {
 705         struct queue_sysfs_entry *entry = to_queue(attr);
 706         struct request_queue *q =
 707                 container_of(kobj, struct request_queue, kobj);
 708         ssize_t res;
 709
 710         if (!entry->show)
 711                 return -EIO;
 712         mutex_lock(&q->sysfs_lock);
 713         res = entry->show(q, page);
 714         mutex_unlock(&q->sysfs_lock);
 715         return res;
 716 }
 717
 718 static ssize_t
 719 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 720                     const char *page, size_t length)
 721 {
 722         struct queue_sysfs_entry *entry = to_queue(attr);
 723         struct request_queue *q;
 724         ssize_t res;
 725
 726         if (!entry->store)
 727                 return -EIO;
 728
 729         q = container_of(kobj, struct request_queue, kobj);
 730         mutex_lock(&q->sysfs_lock);
 731         res = entry->store(q, page, length);
 732         mutex_unlock(&q->sysfs_lock);
 733         return res;
 734 }
 735
 736 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 737 {
 738         struct request_queue *q = container_of(rcu_head, struct request_queue,
 739                                                rcu_head);
 740         kmem_cache_free(blk_requestq_cachep, q);
 741 }
 742
 743 /* Unconfigure the I/O scheduler and dissociate from the cgroup controller. */
 744 static void blk_exit_queue(struct request_queue *q)
 745 {
 746         /*
 747          * Since the I/O scheduler exit code may access cgroup information,
 748          * perform I/O scheduler exit before disassociating from the block
 749          * cgroup controller.
 750          */
 751         if (q->elevator) {
 752                 ioc_clear_queue(q);
 753                 __elevator_exit(q, q->elevator);
 754         }
 755
 756         /*
 757          * Remove all references to @q from the block cgroup controller before
 758          * restoring @q->queue_lock to avoid that restoring this pointer causes
 759          * e.g. blkcg_print_blkgs() to crash.
 760          */
 761         blkcg_exit_queue(q);
 762
 763         /*
 764          * Since the cgroup code may dereference the @q->backing_dev_info
 765          * pointer, only decrease its reference count after having removed the
 766          * association with the block cgroup controller.
 767          */
 768         bdi_put(q->backing_dev_info);
 769 }
 770
 771 /**
 772  * blk_release_queue - releases all allocated resources of the request_queue
 773  * @kobj: pointer to a kobject, whose container is a request_queue
 774  *
 775  * This function releases all allocated resources of the request queue.
 776  *
 777  * The struct request_queue refcount is incremented with blk_get_queue() and
 778  * decremented with blk_put_queue(). Once the refcount reaches 0 this function
 779  * is called.
 780  *
 781  * For drivers that have a request_queue on a gendisk and added with
 782  * __device_add_disk() the refcount to request_queue will reach 0 with
 783  * the last put_disk() called by the driver. For drivers which don't use
 784  * __device_add_disk() this happens with blk_cleanup_queue().
 785  *
 786  * Drivers exist which depend on the release of the request_queue to be
 787  * synchronous, it should not be deferred.
 788  *
 789  * Context: can sleep
 790  */
 791 static void blk_release_queue(struct kobject *kobj)
 792 {
 793         struct request_queue *q =
 794                 container_of(kobj, struct request_queue, kobj);
 795
 796         might_sleep();
 797
 798         if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
 799                 blk_stat_remove_callback(q, q->poll_cb);
 800         blk_stat_free_callback(q->poll_cb);
 801
 802         blk_free_queue_stats(q->stats);
 803
 804         if (queue_is_mq(q)) {
 805                 struct blk_mq_hw_ctx *hctx;
 806                 int i;
 807
 808                 cancel_delayed_work_sync(&q->requeue_work);
 809
 810                 queue_for_each_hw_ctx(q, hctx, i)
 811                         cancel_delayed_work_sync(&hctx->run_work);
 812         }
 813
 814         blk_exit_queue(q);
 815
 816         blk_queue_free_zone_bitmaps(q);
 817
 818         if (queue_is_mq(q))
 819                 blk_mq_release(q);
 820
 821         blk_trace_shutdown(q);
 822         mutex_lock(&q->debugfs_mutex);
 823         debugfs_remove_recursive(q->debugfs_dir);
 824         mutex_unlock(&q->debugfs_mutex);
 825
 826         if (queue_is_mq(q))
 827                 blk_mq_debugfs_unregister(q);
 828
 829         bioset_exit(&q->bio_split);
 830
 831         ida_simple_remove(&blk_queue_ida, q->id);
 832         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 833 }
 834
 835 static const struct sysfs_ops queue_sysfs_ops = {
 836         .show   = queue_attr_show,
 837         .store  = queue_attr_store,
 838 };
 839
 840 struct kobj_type blk_queue_ktype = {
 841         .sysfs_ops      = &queue_sysfs_ops,
 842         .release        = blk_release_queue,
 843 };
 844
 845 /**
 846  * blk_register_queue - register a block layer queue with sysfs
 847  * @disk: Disk of which the request queue should be registered with sysfs.
 848  */
 849 int blk_register_queue(struct gendisk *disk)
 850 {
 851         int ret;
 852         struct device *dev = disk_to_dev(disk);
 853         struct request_queue *q = disk->queue;
 854
 855         if (WARN_ON(!q))
 856                 return -ENXIO;
 857
 858         WARN_ONCE(blk_queue_registered(q),
 859                   "%s is registering an already registered queue\n",
 860                   kobject_name(&dev->kobj));
 861
 862         /*
 863          * SCSI probing may synchronously create and destroy a lot of
 864          * request_queues for non-existent devices.  Shutting down a fully
 865          * functional queue takes measureable wallclock time as RCU grace
 866          * periods are involved.  To avoid excessive latency in these
 867          * cases, a request_queue starts out in a degraded mode which is
 868          * faster to shut down and is made fully functional here as
 869          * request_queues for non-existent devices never get registered.
 870          */
 871         if (!blk_queue_init_done(q)) {
 872                 blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
 873                 percpu_ref_switch_to_percpu(&q->q_usage_counter);
 874         }
 875
 876         blk_queue_update_readahead(q);
 877
 878         ret = blk_trace_init_sysfs(dev);
 879         if (ret)
 880                 return ret;
 881
 882         mutex_lock(&q->sysfs_dir_lock);
 883
 884         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 885         if (ret < 0) {
 886                 blk_trace_remove_sysfs(dev);
 887                 goto unlock;
 888         }
 889
 890         ret = sysfs_create_group(&q->kobj, &queue_attr_group);
 891         if (ret) {
 892                 blk_trace_remove_sysfs(dev);
 893                 kobject_del(&q->kobj);
 894                 kobject_put(&dev->kobj);
 895                 goto unlock;
 896         }
 897
 898         mutex_lock(&q->debugfs_mutex);
 899         q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
 900                                             blk_debugfs_root);
 901         mutex_unlock(&q->debugfs_mutex);
 902
 903         if (queue_is_mq(q)) {
 904                 __blk_mq_register_dev(dev, q);
 905                 blk_mq_debugfs_register(q);
 906         }
 907
 908         mutex_lock(&q->sysfs_lock);
 909         if (q->elevator) {
 910                 ret = elv_register_queue(q, false);
 911                 if (ret) {
 912                         mutex_unlock(&q->sysfs_lock);
 913                         mutex_unlock(&q->sysfs_dir_lock);
 914                         kobject_del(&q->kobj);
 915                         blk_trace_remove_sysfs(dev);
 916                         kobject_put(&dev->kobj);
 917                         return ret;
 918                 }
 919         }
 920
 921         blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
 922         wbt_enable_default(q);
 923         blk_throtl_register_queue(q);
 924
 925         /* Now everything is ready and send out KOBJ_ADD uevent */
 926         kobject_uevent(&q->kobj, KOBJ_ADD);
 927         if (q->elevator)
 928                 kobject_uevent(&q->elevator->kobj, KOBJ_ADD);
 929         mutex_unlock(&q->sysfs_lock);
 930
 931         ret = 0;
 932 unlock:
 933         mutex_unlock(&q->sysfs_dir_lock);
 934         return ret;
 935 }
 936 EXPORT_SYMBOL_GPL(blk_register_queue);
 937
 938 /**
 939  * blk_unregister_queue - counterpart of blk_register_queue()
 940  * @disk: Disk of which the request queue should be unregistered from sysfs.
 941  *
 942  * Note: the caller is responsible for guaranteeing that this function is called
 943  * after blk_register_queue() has finished.
 944  */
 945 void blk_unregister_queue(struct gendisk *disk)
 946 {
 947         struct request_queue *q = disk->queue;
 948
 949         if (WARN_ON(!q))
 950                 return;
 951
 952         /* Return early if disk->queue was never registered. */
 953         if (!blk_queue_registered(q))
 954                 return;
 955
 956         /*
 957          * Since sysfs_remove_dir() prevents adding new directory entries
 958          * before removal of existing entries starts, protect against
 959          * concurrent elv_iosched_store() calls.
 960          */
 961         mutex_lock(&q->sysfs_lock);
 962         blk_queue_flag_clear(QUEUE_FLAG_REGISTERED, q);
 963         mutex_unlock(&q->sysfs_lock);
 964
 965         mutex_lock(&q->sysfs_dir_lock);
 966         /*
 967          * Remove the sysfs attributes before unregistering the queue data
 968          * structures that can be modified through sysfs.
 969          */
 970         if (queue_is_mq(q))
 971                 blk_mq_unregister_dev(disk_to_dev(disk), q);
 972
 973         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 974         kobject_del(&q->kobj);
 975         blk_trace_remove_sysfs(disk_to_dev(disk));
 976
 977         mutex_lock(&q->sysfs_lock);
 978         if (q->elevator)
 979                 elv_unregister_queue(q);
 980         mutex_unlock(&q->sysfs_lock);
 981         mutex_unlock(&q->sysfs_dir_lock);
 982
 983         kobject_put(&disk_to_dev(disk)->kobj);
 984 }